This lesson is covered in more detail in Week 7 of Introduction to Sindarin

The basic interrogative words, or question words (Who, What, Why etc.) are very useful in forming sentences.
The verb endings and prepositions that you are introduced to here will be covered in detail in later lessons.

What? Who?

The word Man means both 'what' and 'who'
Man te? What is it? Who is it?
Man sa? What is that? Who is that?
Man e lû? What (is) the time?
Man sad? What place? (alternative for 'Where?')
Man agoreg? What did you do?
Man na e fen? Who is at the door?
Alternative
To avoid ambiguity when asking 'Who is it?' you could also ask
Man pen? What person? (Who?)
'Man' is the only attested Sindarin interrogative. All others are reconstructed.

Where?

Mivan? In what (place)?
Navan? At what (place)?
Oman? From what (place)?

Mivan i degil nîn? Where is my pen? (In what place is my pen?)
Navan agoreg? Where did you do that? (At what place did you do that?)
Navan e mar? Where is the house?
Navan ci? Where are you? (if you aren't within the same locale)
Mivan ci? Where are you? (if you're within the same locale or building)
Oman i ost tôl? Where is the city he is coming from? (From what place is the city he is coming?)

Remember you've already seen Navan before in Lesson 3 - Navan dorthog?
Alternative
Mas? Where?
This word was reconstructed from Quenya.

When?

Mallú agoreg? When did you do that?
Mallú ci onnen? When (were) you born?
Mallú iavas? When is autumn?
Mallú telithar? When will they come?
Alternatives
Na van lû? At what time?
Mar? When? This word was reconstructed from Quenya.

How?

Manen agoreg? How did you do that?
Manen istog? How do you know?
Manen ven hirnig? How did you find us?
Alternative
Naman? How? 'With what?'

Why?

Amman níniol? Why are you crying?
Amman agoreg? Why did you do that?
Amman en ell luin? Why is the sky blue?
Amman gelia Edhellen? Why is he studying Elvish?

For what purpose? (Why?)

Amman theled agoreg? Why did you do that? (For what purpose did you do that?)
Amman theled anírog istol? Why do you want to know? (For what purpose do you want to know?)

Other questions

O van? From what? About what?
Be van? According to whom?

There are many other questions you can ask when you combine the question words here with the prepositions in Lesson 13

Further vocabulary